This invention relates to a radiation curable polyurethane oligomer composition useful as a print laminating adhesive.
The use of photopolymerizable acrylate terminated urethane oligomers have been disclosed in various applications. U.S. Pat. No. 5,087,686 issued Feb. 11, 1992 to C. Ansell, et al., describes curable polyurethane oligomers capped with acrylates and alcohols which are used in pressure sensitive adhesives. U.S. Pat. No. 4,786,586 issued Nov. 22, 1988 to S. Lee, et al. discloses acrylate terminated urethane oligomers having a polybutadiene or polybutene backbone and which are used as photoemulsion laminate layers in photographic film. U.S. Pat. No. 4,789,625 issued Dec. 6, 1988 to S. Ellerstein, et al., also discloses acrylate terminated urethane oligomers useful as photoemulsion laminates in photographic film wherein the backbone is derived from an alkanediol.
Other photopolymerizable acrylate terminated urethane compositions include polyurethane poly(meth)acrylates which contain tetramethylxylylenediisocyanate as the main polyisocyanate component in laminating film applications as disclosed in U.S. Pat. No. 5,204,379 issued Apr. 20, 1993 to T. Kabota, et al.; acryl urethane oligomers with a UV absorber as shown in U.S. Pat. Nos. 4,129,667 issued Dec. 12, 1978 and 4,135,007 issued Jan. 16, 1979 to D. Lorenz, et al.; and vinylurethane monomers disclosed in U.S. Pat. No. 3,907,865 issued Sep. 23, 1975 to N. Miyata, et al.
Despite the many known acrylate containing polyurethanes and other photopolymerizable compositions, there still is the need for a print laminating adhesive composition that can provide rapid curing and strong adhesion while having low volatility and odor, is not toxic and possesses other environment friendly characteristics.